[Repeater Question]

I am new to GMRS

I subscribed to a GMRS repeater but having trouble programming into my new BaoFend UV5G

I have input and output channels

are the Input channels RX or Tx

I know this is simple. thank you for the help

[High swr on GMRS box]

I have a radiodditty GMRS mobile radio that I built into an ammunition box for portability and connected to a lithium battery. The battery box is plastic/nonmetal. When I checked the SWR of the antenna, I get a very high reading, between five and 10. Is there any way to reduce the SWR? Do I need a ground plane? Is there a way to add a ground to the system, such as a wire connected to a post in the ground? The radio box was intended to be used as a mobile unit to coordinate multiple smaller GMRs radios. Thank you